Initial implementation of a generic UI component (#61)

* Add generic component

* Add validation. Rename to widgetRenderer

* Remove test code from splash screen

* Clean up infobox

* Fix styling/layout

* Move test code into unit test

* Replace <input> and <labe> by <TextField> and <Text> respectively. Fix style.

* Replace InfoBoxComponent with UI fabric MessageBar. Fix styling for TextField

* Use MessageBar for error message

* Rename WdigetRendererComponent to SmartUiComponent

src/Explorer/Controls/SmartUi/InputUtils.ts

@@ -0,0 +1,35 @@
+/* Utilities for validation */
+
+export const onValidateValueChange = (newValue: string, minValue?: number, maxValue?: number): number => {
+  let numericValue = parseInt(newValue);
+  if (!isNaN(numericValue) && isFinite(numericValue)) {
+    if (minValue !== undefined && numericValue < minValue) {
+      numericValue = minValue;
+    }
+    if (maxValue !== undefined && numericValue > maxValue) {
+      numericValue = maxValue;
+    }
+
+    return Math.floor(numericValue);
+  }
+
+  return undefined;
+};
+
+export const onIncrementValue = (newValue: string, step: number, max?: number): number => {
+  const numericValue = parseInt(newValue);
+  if (!isNaN(numericValue) && isFinite(numericValue)) {
+    const newValue = numericValue + step;
+    return max !== undefined ? Math.min(max, newValue) : newValue;
+  }
+  return undefined;
+};
+
+export const onDecrementValue = (newValue: string, step: number, min?: number): number => {
+  const numericValue = parseInt(newValue);
+  if (!isNaN(numericValue) && isFinite(numericValue)) {
+    const newValue = numericValue - step;
+    return min !== undefined ? Math.max(min, newValue) : newValue;
+  }
+  return undefined;
+};